The following account of the prior art relates to one of the areas of application of the present application, hearing aids.
As the market for ‘Receiver in the Ear’ (RITE) hearing aids (HA's) increases, more RITE modules with different receivers (speakers) will come to co-exist in the coming years. A strategy for identifying and distinguishing these RITE modules is needed to ensure that future HA solutions will not impose damage and/or produce uncomfortable (or too weak) sound levels to the end user in case of attaching a wrong RITE module, e.g. one with higher (or lower) sensitivity than expected during fitting. A mechanical differentiation between different modules is possible, e.g. by having different connectors with different mechanical properties, e.g. from, is possible. Such solution is, however, not attractive due to cost of production and the complexity of handling of several different variants of ‘the same’ component/module.
In practice, each receiver has different physical properties (e.g. frequency response) depending firstly on receiver type (intended technical specifications) and secondly on product variations within a given type. Knowledge of the exact properties (e.g. response) of a given receiver can be used to obtain a more precise amplification (possibly without knowing its type). Knowledge of the properties (e.g. frequency response) of a particular receiver is useful not only in a hearing aid where the receiver is located in a separate body but also in a hearing aid, where the receiver is implemented in the hearing aid-body, e.g. together with a processing unit.
Further, WO 2009/065742 A1 addresses the problem of identification of individual receiver properties as well as of identifying different types of receivers. The term type (or model or version) is used to mean identification of a class of receivers comprising a larger number of individual items, which are intended to have the same properties. A type of receiver can e.g. be characterized by its intended technical specifications, such as its input sensitivity and/or max output volume. The term type of receiver is on the other hand not intended to provide a unique identification of the individual receiver (such as its individual detailed frequency response).
US 2002/0015506 A1 deals with a selector module or component tester provided to a user for selecting one of multiple acoustical formats of a hearing aid device. Preferably, the acoustical format defines an acoustical response of the hearing aid device for an entire continuous range of frequencies detectable by a human ear. The component tester is e.g. used to test a receiver or speaker of a hearing aid device. Generally, a compensation factor is assigned to a tested component depending upon a variation of the component from a standard. When a device such as a hearing aid is assembled including a particular tested component, the compensation factor corresponding to the component is programmed in the device so that a response of the device conforms to a desired standard or norm.